So-called deployment clasp closures are known in the prior art that allow the watch to be threaded on easily when the clasp is folded out and to then tighten the wrist band in closed position. This type of closure generally comprises a metal cover that closes over the folding tabs, one end of which is attached to the end of one of the strand of the watch band, while the end of the other strand is fixed to an end of the cover. The fastener can be locked by means of a pushbutton mechanism acting in a transverse direction.
Such closures are often used in combination with watch bands that have strands formed by rows of articulated metal links. In this case the adjustment of the length of the watch band is achieved by removing one or more links at the end of one or more strands before attaching these ends to the closure.
In the case of rubber watch bands the length is generally adjusted simply by cutting off a desired length of the band at the attachment end of the strand before then joining this end of the strand to the closure again or to a connection piece of the closure. However, this simple solution requires adapting the closure or at least an attachment piece of the closure to the strand to conceal the visible cut edge of the strand and also prevent rotation of the end of this strand in relation to the closure in order to prevent the cut edge of the strand from protruding onto the skin of the user and rendering use of such a watch band particularly uncomfortable. Therefore, in the case of a plastic watch band the abovementioned length adjustment by simple cutting cannot be made without modifying the structure of the closure, which prevents the use of the same closures for bands made of plastic or leather and even metal or ceramic, and therefore causes substantial losses in productivity.
Closure systems adapted to any type of watch band, i.e. made of leather, fabric, plastic or metal, are additionally known such as the closure described in document EP 0081616, for example. In this type of closure the ends of the strands 9, 13 of the watch band can be fixed by means of connector bars 10, 14 in different pairs of holes 7, 11 of circular arc-shaped tubular pieces 1, 2 engaging into one another to define a nominal length for the band, while locking assured by cooperation of a rack 6 and an elastic element 23 allows a quick and easy fine adjustment thereof. However, this type of closure has a complex structure that is difficult to machine and poses reliability problems with respect to the locking system compared to classic deployment clasp closures.
Special devices for attaching a watch band strand to a deployment clasp closure are also known, such as the system described in the Swiss patent CH 689534, for example, according to which studs 13, 14 are respectively arranged in front of a loop 19 of the closure and on one of the tabs of the deployment clasp to cooperate with perforations 21-26 of a strand 6 of the watch band. However, this type of device is only suitable for watch bands with perforated strands and modifies the structure of the deployment clasps of the closure, which restricts the possible uses thereof considerably.
Therefore, there is a need for watch bands without the known limitations of the prior art in terms of structural shortcomings and/or locking reliability.